Technical Abstract:
Soil quality is a concept of quantifying characteristics of the soil relative to various soil function, but in practice it is used very little because of time and cost constraints. Our objectives with this research were to (1)identify whether sensor-based soil EC and terrain attribute information can be used to predict soil quality on claypan soils and (2) evaluate spatial characteristics of soil quality indicators for claypan soils. In June 2002, 255 soil samples were collected on a 10 to 30 m grid spacing within a 5.5 ha claypan soil field. Soil sample depths were 0 to 7.5 cm, 7.5 to 15 cm and 15 to 30 cm. Samples were analyzed for physical, chemical, and microbial properties as soil quality indicators. Sensor-based measurements included soil EC, elevation, slope, and aspect. Factor analysis, ANOVA, and regression analysis were used to identify those soil quality indicators that were best related to sensor-based soil EC and terrain attributes. Geostatistical analysis was used to identify the spatial characteristics of soil quality indicators for claypan soils. Bulk density and soil moisture were found to exhibit strong spatial dependency over a fairly short distance (< 20 m). The results of this research will be used to explore potential opportunities for improving soil quality and, in turn, water quality and crop production.